1. Spread and stretch the sliced beef on your working table.
2. Arrange the filling on the sliced beef: sausage strips, cheese strips, sliced eggs, pork fat and some ground liver.
3. Roll the sliced beef with all the filling inside and secure with a thread or string.
4. Repeat the procedure for the two remaining beef slices.
5. On a pot, place the beef rolls and put the water, the remaining ground liver, grated cheese, chopped onions, bay leaves, ground black pepper and salt.
6. Cover the pot and bring to a boil. Simmer for one hour.
7. Add the vinegar and continue to simmer of another hour or until beef is tender.
8. Slice the beef morcon, arrange on a platter and top with the gravy on top.